On 6/11/25 7:55 AM, Uwe Kleine-König wrote:
Hello Marek,
Hi,
I wonder how this device works in rpios, I didn't find a matching driver
(but I also didn't try more than two minutes).
The installation guide is here, download the PDF:
https://argon40.com/blogs/argon-resources/argon-fan-hat-installation-guide
Which leads to this script, which you download on the RPI and (better
not without reading it first and understanding it) run:
https://download.argon40.com/argonfanhat.sh
Which downloads more scripts, installs systemd services which run other
scripts, but ultimately this convoluted scripting leads to a single
register write for this fan.
On Wed, Jun 11, 2025 at 12:07:27AM +0200, Marek Vasut wrote:
diff --git a/drivers/pwm/pwm-argon-fan-hat.c b/drivers/pwm/pwm-argon-fan-hat.c
new file mode 100644
index 000000000000..3d04abdbd349
--- /dev/null
+++ b/drivers/pwm/pwm-argon-fan-hat.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Marek Vasut
+ */
* Limitations:
* - fixed period (which?)
* - no support for offset/polarity
If you can find out if it completes a period when reconfigured that
would also be nice to document.
This device is really trivial, but for completeness' sake: If there is a
data sheet publicly available, please add a link here.
There is nuvoton MS51FB9AE microcontroller on the underside of the
board, which I think does the I2C communication and PWM generation. The
firmware source does not seem available.
I can see some signal on the FAN itself, it is horribly noisy, but with
sufficient filtering I can see they change the PWM period, from some 0
Hz to 120 kHz , with duty cycle being some 10% (but I might be wrong,
the signal is not great).
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/pwm.h>
+
+static int argon_fan_hat_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
Can you please implement the new-style callbacks?
Sure
[...]
+static const struct pwm_ops argon_fan_hat_pwm_ops = {
+ .apply = argon_fan_hat_pwm_apply,
Can you read back the configuration? If yes then please implement
.read_waveform().
Nope, reading from the I2C device stops the fan.
Rest is fixed in V2, thanks.
--
Best regards,
Marek Vasut
